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Old 2018-11-18, 11:59 PM   #2191
MuniAddict
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High gear slipping issue possible fix

I know that the current version schlumpf hub fixed the issue of intermittent slipping of the knurled bearing in the bearing cap. But for those with previous versions like mine, I came up with a fairly simple solution that seems to be working very well so far. Even with the bearing caps tightened to the correct torque, the knurled bearing can still slip inside the cap. I have assumed this is because the inside of the cap is smooth and there's nothing for the knurled surface to "grab", and also because on occasion, gear oil can seep into that area and cause the bearing to slip.

My idea was to tap a small hole into the bottom of the bearing cap on the knurled side, and insert a stop screw just far enough to make contact with the knurled surface but without damaging the bearing. After several test rides and applying even more back pressure then had caused the slipping issue before, I was unable to get the bearing to slip inside the cap. I found that a cone-shaped stop screw, or one with a point on it is best since the point can rest in between 2 knurled areas of the bearing, effectively preventing it from slipping.

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Old 2018-11-19, 12:46 AM   #2192
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High gear slipping possible fix

Quote:
Originally Posted by MuniAddict View Post
... the point can rest in between 2 knurled areas of the bearing, effectively preventing it from slipping...
How do you know if the point lands in a valley rather than on a slope or even a top of the knurls? Or can you nudge it to a valley before everything is fixed in place?

And do you loctite the screw? I guess you can't tighten it very much or you would damage the bearing, and so with all the changes in force direction that come from normal riding, it would probably loosen quite soon without loctite.
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Old 2018-11-19, 12:58 AM   #2193
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Originally Posted by Klaas Bil View Post
How do you know if the point lands in a valley rather than on a slope or even a top of the knurls? Or can you nudge it to a valley before everything is fixed in place?

And do you loctite the screw? I guess you can't tighten it very much or you would damage the bearing, and so with all the changes in force direction that come from normal riding, it would probably loosen quite soon without loctite.
Yes I did use blue Loctite in the event I need to make an adjustment later on. It's in there quite securely even without the Loctite. The fine point on the stop screw is seated against the knurled surface of the bearing very firmly and may have initially hit a raised portion but then likely slid past that into the lowest area between two knurls. I was also thinking that if one stop screw was not sufficient then two could be used on opposing sides (approximately 5 & 7 o'clock) on the bottom of the cap
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Last edited by MuniAddict; 2018-11-19 at 01:02 AM.
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Old 2018-11-19, 08:04 AM   #2194
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Quote:
Originally Posted by MuniAddict View Post
I know that the current version schlumpf hub fixed the issue of intermittent slipping of the knurled bearing in the bearing cap. But for those with previous versions like mine, I came up with a fairly simple solution that seems to be working very well so far. Even with the bearing caps tightened to the correct torque, the knurled bearing can still slip inside the cap. I have assumed this is because the inside of the cap is smooth and there's nothing for the knurled surface to "grab", and also because on occasion, gear oil can seep into that area and cause the bearing to slip.

My idea was to tap a small hole into the bottom of the bearing cap on the knurled side, and insert a stop screw just far enough to make contact with the knurled surface but without damaging the bearing. After several test rides and applying even more back pressure then had caused the slipping issue before, I was unable to get the bearing to slip inside the cap. I found that a cone-shaped stop screw, or one with a point on it is best since the point can rest in between 2 knurled areas of the bearing, effectively preventing it from slipping.
This is potentially very dangerous thing to do for your hub, you would have to be very gentle with the pressure you use on screw. Point pressure on the bearings is what often causes them to fail.

Roger
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Old 2018-11-19, 02:08 PM   #2195
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Originally Posted by rogeratunicycledotcom View Post
This is potentially very dangerous thing to do for your hub, you would have to be very gentle with the pressure you use on screw. Point pressure on the bearings is what often causes them to fail.

Roger
thanks for that input Roger. Do you think using two stop screws with flat heads - one at 5 o'clock and the other at 7 o'clock position - would be a better idea?
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Old 2018-11-19, 02:32 PM   #2196
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thanks for that input Roger. Do you think using two stop screws with flat heads - one at 5 o'clock and the other at 7 o'clock position - would be a better idea?
I am not sure applying any point pressure to the bearings is a good idea if you can help it. To split hardened shells, this is how you do it if you "want" to break them. I actually think that a pointed may be better than flat. 2 may be better than one as you can less load for the same effect. Either way I would not say that it is a good solution though. Even though this seams to have solved your slip problem, I don't think it is ideal. Sorry

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Old 2018-11-19, 03:43 PM   #2197
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Originally Posted by rogeratunicycledotcom View Post
I am not sure applying any point pressure to the bearings is a good idea if you can help it. To split hardened shells, this is how you do it if you "want" to break them. I actually think that a pointed may be better than flat. 2 may be better than one as you can less load for the same effect. Either way I would not say that it is a good solution though. Even though this seams to have solved your slip problem, I don't think it is ideal. Sorry

Roger
My objective is to have the stop screw(s) make only minimal contact with the surface of the bearing so that any possible slippage of the bearing would be impeded without penetrating into the bearing surface. Another less risky option might be to apply a small strip of grip tape to both the frame cap and bottom cap. I had previously used a strip of aluminum tape which which would mold to the knurled bearing preventing slippage. But this was short-lived as it would wear away in fairly short order, so I would assume the same would happen with griptape.
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Last edited by MuniAddict; 2018-11-19 at 03:48 PM.
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Old 2018-11-19, 03:49 PM   #2198
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Not necessarily, the grip tape has thickness and hence will put pressure on the bearing as well if it goes all the way around the bearing housing. Although it may work if it is only a narrow strip across and does not go all the way around it. Hmmm, I would be more confident of trying that out than trying to put a screw thread on to it.
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Old 2018-11-19, 04:07 PM   #2199
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Originally Posted by rogeratunicycledotcom View Post
Not necessarily, the grip tape has thickness and hence will put pressure on the bearing as well if it goes all the way around the bearing housing. Although it may work if it is only a narrow strip across and does not go all the way around it. Hmmm, I would be more confident of trying that out than trying to put a screw thread on to it.
I would think the ideal solution for previous models to the current version which fixed this issue, would be a bearing cap with the same knurled surface built into the cap, which would provide the optimum, interlocking fit.
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Old 2018-11-19, 09:53 PM   #2200
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I would think the ideal solution for previous models to the current version which fixed this issue, would be a bearing cap with the same knurled surface built into the cap, which would provide the optimum, interlocking fit.
The ideal solution might be to send it to Jakob for modification...

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Old 2018-11-20, 12:04 AM   #2201
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What are you doing that's causing your hub to slip so much It's literally never happened for me. I don't do hardcore DH Muni but I do ride up and down on-road hills that would scare some cyclists away, so do find myself absolutely ragging it with pedal pressure sometimes.
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Old 2018-11-20, 12:35 AM   #2202
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I think my issue was hard use of the disk brake coupled with bolts coming a little loose. There's a fine line between too tight and too loose with bearings you know that you can't easily replace.
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Old 2018-11-20, 06:58 PM   #2203
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I dont see the pointed screw version as a risk, since the bearimg cant go anywhere. its firmly jammed in the circle of the frame(dont know the word) - shold be. and therefore its theoreticaly unpossible to deform by giving pressure on one point/side. Like a rim that cant go oval cause its kept in circle by the spokes.

I would try to drill a little dip into the bearing for the screws peak to dig in. Might asked my dentist for help there

I wrecked my knee two times with the slippin schlumpf - went back to rim breaks for now...
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Old 2018-11-21, 03:01 AM   #2204
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What are you doing that's causing your hub to slip so much It's literally never happened for me. I don't do hardcore DH Muni but I do ride up and down on-road hills that would scare some cyclists away, so do find myself absolutely ragging it with pedal pressure sometimes.
Apparently enough people were having the slipping issue that it prompted Florian to totally redesign the hub which now incorporates a "torque block", expressly designed to prevent slippage in high gear.
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Old 2018-11-23, 01:57 AM   #2205
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Quote:
Originally Posted by mowcius View Post
The ideal solution might be to send it to Jakob for modification...

https://www.facebook.com/flansberriu...73381552895176
I was going to post it here hahaha.

So far so good on mine! I haven't ridden that much since I built it back, but I have tested it with loose bearing caps even and it wont slip!

My schlumpf sat in a box for about a year, because I was tired of riding it while it slipped and ruining my bearings because I rode it too hard. I ended up giving a try on a first gen Schlumpf hub, which had the little arm bolted on the frame. Since that hub couldn't slip, I was actualy able to ride uphill without worrying about falling off, I could push as hard as I wanted in either direction. I took my hub out of its box, ordered a new set of bearings, took it apart, modified it, and back together! I only use it on road or gravel now, I've been rough on it in the past while riding muni, it doesn't like my type of riding.

I'd be willing to modify existing hubs, but it voids Schlumpf's warranty!

Send me private messages, emails, or facebook messages, or instagram for the interested
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